Well, turned out to not be the secondaries at all (however, true that they were no opening up yet). Instead, it was timing. Threw the timing light on it and it was 5 degrees ATDC. Bumped it to 10 BTDC and it was an instant 10MPH gain. It's now right around 39MPH, but that was also loaded up with 5 people, wake boards up on the pole, and the bimini top up.